Energy
What are the SI (international) units for energy?
Joules
Heat always flows from _______ objects to ________ objects.
Hot to cold
What atomic particle has no charge?
Neutrons
What gas is always present as a reactant in every combustion reaction?
Oxygen
What are the SI (international) units of mass?
Grams
Electrical energy is caused by the flow of ______________.
Electrons (charged particles)
What temperature scale is based on the freezing and boiling point of water?
Celsius
The starting material(s) for a reaction are called ________________.
Reactants
Is a combustion reaction an exothermic process, endothermic process, or neither?
Exothermic. Combustion reactions release energy in the form of heat, sound, and light.
What type of system allows heat to be exchanged with the surroundings but not matter?
A Closed System
Energy cannot be _____________ or ______________ but it can be __________________.
Created
Destroyed
Transferred/Transformed
When does heat stop flowing between two objects?
This type of reaction absorbs energy from its surroundings.
Endothermic
The fuel for a combustion reaction that is only made of carbon and hydrogen is known as a ______________.
Hydrocarbon
Isotopes are atoms of the same element that have a different number of ___________.
Neutrons
For an exothermic reaction, how is the energy of the reactants related to the energy of the products?
The reactants are at a higher energy than the products.
Fast moving particles transfer energy to slow moving particles when they _______________ with them.
Collide
The minimum amount of energy required to start a chemical reaction is known as __________________.
Activation energy
What product is present in an incomplete combustion reaction that isn't present in a complete combustion reaction?
Carbon monoxide (CO)
What two types of reactions do not follow the law of conservation of matter?
Fusion and fission reactions
According to our textbook, what percentage of energy is wasted in the U.S.?
68.2%
What property of water causes San Francisco to usually be about 20 degrees cooler then Stockton?
Why do the surroundings get colder during an endothermic reaction?
Because the reaction is absorbing energy (heat) from the surroundings.
What do combustion reactions produce that we use to do work. For example to shoot a rocket into space or to push a piston in a car.
Expanding gases
What happens to the mass of the reactants in a nuclear reaction?
Some of it is converted into energy